Specimen and current measuring method

Active Publication Date: 2015-05-21
SUBARU CORP
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Benefits of technology

This patent aims to provide a specimen that can help determine the shape and size of a fastener, as well as the machining conditions that led to the fastener's design. The patent also includes a current measuring method for the specimen. These features can help prevent the fastener from discharging.

Problems solved by technology

On the other hand, the composite material contains conductive fibers such as carbon fibers, and may thus serve as an unintended current path in connection with the design of the structure when a short circuit or lightning strike occurs.
Thus, the composite material involves a more complicated current path than metallic materials.
A particularly complicated current path is involved in a carbon fiber laminate in which a plurality of layers with different fiber directions is laminated.
However, in these inventions, it is not possible to measure a current in an out-of-plane direction that crosses the surface of in a laminate composite material.
Additionally, a propagation mechanism for a current in an out-of-plane direction in the laminate composite material has not been theoretically clarified.
However, both JP-A No. 2013-050306 and JP-A No. 2013-053858 involve a specimen that is a single laminate composite material and fail to disclose an example of current measurement intended to clarify a propagation mechanism for a current in a specimen of two laminate composite materials coupled together with a fastener or conditions for a preferred coupling area.
However, conventionally available fasteners are special products and expensive, resulting in having an impact on fuselage manufacturing costs.
On the other hand, less expensive fasteners are also available, but when such fasteners are used without any modification, the fasteners may cause discharge because these fasteners offer large contact resistance to the composite material.

Method used

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  • Specimen and current measuring method
  • Specimen and current measuring method
  • Specimen and current measuring method

Examples

Experimental program
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Embodiment Construction

[0057]Implementations of a specimen of a laminate composite material and a current measuring method according to the present invention will be described below with reference to the drawings.

[0058](First Implementation)

[0059]FIG. 1 is a laminate composite material and a specimen (test piece) of the laminate composite material to which a current measuring method according to the first implementation is applied.

[0060]The composite material to be measured is fiber reinforced plastic including a resin reinforced with fibers, and is carbon fiber reinforced plastic (CFRP) containing carbon fibers. As illustrated in FIG. 1A, a specimen M is a shaped like a strip.

[0061]Furthermore, as illustrated in FIG. 1B, the specimen M is a laminated composite material formed by laminating eight prepregs P1 to P8 serving as the composite material sheets of the present invention and each including a plurality of carbon fiber bundles arranged along a predetermined direction and impregnated with an uncured ...

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Abstract

Composite material sheets containing conductive fibers are laminated, and release films are interposed between the sheets so as to extend from one end to the center of the sheets. The sheets are heated under pressure to shape a composite material. Discrete conductive wires through which a measurement current is passed are connected to end surfaces of the respective layers in the composite material on the side on which the release films are interposed. A common conductive wire through which the measurement current is passed is connected to a surface of one of an uppermost layer and a lowermost layer at an end of the composite material opposite to the side on which the release films are interposed. A current is passed between the common conductive wire and the discrete conductive wires. Currents in the respective layers are sequentially or simultaneously measured using an ammeter.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS[0001]The present application claims priority from Japanese Patent Application Nos. 2013-237927 filed on Nov. 18, 2013, 2014-068034 filed on Mar. 28, 2014 and 2014-172183 filed on Aug. 27, 2014, the entire contents of which are hereby incorporated by reference.BACKGROUND[0002]1. Technical Field[0003]The present invention relates to a specimen used to measure a current flowing through a composite material containing conductive fibers and a current measuring method for the specimen.[0004]2. Related Art[0005]In recent years, the application of composite materials such as carbon fiber reinforced plastic (CFRP) to structures has been spreading widely. For example, such composite materials have been applied in a variety of fields, for example, to fuselages of airplanes, frameworks of automobiles, and blades of windmills. On the other hand, the composite material contains conductive fibers such as carbon fibers, and may thus serve as an unintended cur...

Claims

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Application Information

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IPC IPC(8): G01R19/00G01R15/18G01R31/00G01R19/10
CPCG01R19/0092G01R31/008G01R15/181G01R19/10B32B5/22B32B5/24B32B5/26B32B5/28B32B27/04B32B27/12B32B2250/03B32B2250/05B32B2250/24B32B2250/40B32B2250/42B32B2250/44B32B2260/021B32B2260/023B32B2260/046B32B2262/106B32B2307/202B32B2457/00B32B2605/18G01N27/045B32B3/08B32B3/266B64F5/60
InventorKAWASHIMA, AIFUJITA, HIROYASUSEKINE, NAOYUKI
OwnerSUBARU CORP